Dock seals form a weather seal between a trailer and a loading bay. Various types of dock seals have been developed and are know in the industry. Compression seals that seal against the rear end of the trailer are disclosed in U.S. Pat. Nos. 3,230,675 and 6,170,205. Compressible seals that engage the sides and top end of a trailer are disclosed in U.S. Pat. Nos. 4,679,364 and 4,213,279. Inflatable or expanding seals that engage the sides and top of a trailer are described in U.S. Pat. Nos. 3,714,745; 3,939,614; 4,020,607 and 5,109,639. A loading dock shelter with side curtains mounted to side frames and a head curtain mounted to a top wall is disclosed in U.S. Pat. No. 3,403,489. A loading dock shelter with side and head curtains and compressible springs is disclosed in U.S. Pat. No. 3,826,049. A canopy with vertical side members and compressible springs and a horizontal member is disclosed in U.S. Pat. No. 4,365,452. Various problems exist with each of these dock seals. For example, conventional compression seals are impractical for large variations of trucks and trailers, especially those with rear steps or tail gates. Conventional vertically hung wiping seals or shelters do not provide as good of seal efficiency as a compression seal.
Conventional trailer seals do not effectively prevent rainwater from spilling off the top of a trailer and into the loading bay. This is particularly problematic for loading bays where the ground or approach in front of the bay slopes down toward the loading bay. When a trailer enters or is parked in the loading bay, the top of the trailer is not level, and slopes down toward the bay. Rain water collecting on the large top surface of the trailer is drawn by gravity to flow down its top surface, off its rear end and into the loading bay. Wind can increase the force with which the water is driven down the trailer top and off its rear end. Wind alone can blow water across the top of a parked trailer on a level approach. The result is a slippery, dangerous, uncomfortable and costly situation where water spills or sprays onto the building floor, dock workers, cargo and cargo moving equipment.
Another problem with conventional loading bay seals is that trailers come in a variety of heights. A seal designed to engage the top of a taller trailer will not extend down enough to effectively engage the top of a smaller trailer. Even if the seal extends down far enough to engage the top of the trailer, the seal will not engage the top of the smaller trailer with sufficient force to push away and divert rainwater accumulating on the top of the trailer or prevent the wind from blowing the rainwater under the seal and into the loading bay. As a result, smaller trailers are not properly sealed and rainwater is free to enter the loading bay. Seals designed to properly engage the top of a smaller trailer will not accommodate a larger trailer. Taller trailers will damage the seal when backed into the bay. Any seal or partial seal they make will be ineffective in keeping wind and rainwater out of the loading bay.
A further problem with conventional loading bay seals is that trailers come in a variety of widths. Top seals designed to engage a narrow trailer will not accommodate or fully extend across the top of a wider trailer. Wider trailers can damage the seal, and they will not be properly sealed to prevent wind and rainwater from entering the loading bay.
A still further problem with conventional loading bay trailer seals is that trailers are frequently off center or miss-spotted when backed into the bay. The trailer is not centered with the door opening. One side of the trailer is closer to its side of the door opening, and the other side of the trailer is further away from its side of the door opening. This creates a sealing problem because one side of the trailer will improperly engage its side seal, and the other side of the trailer will altogether miss or improperly engage its side seal. Moreover, a portion of the trailer top will fail to properly engage the top seal, and can miss the top seal altogether.
A still further problem with conventional loading bay trailer seals is that trailers are frequently backed into a bay at an angle. The back end of the trailer is not parallel to the wall of the building. As a result, the sides and top of the trailer do not simultaneously engage the seal. Many seals are not designed to handle this disjointed engagement. As a result, the corners of the trailer can snag or tear the seal, or the unevenly distributed forces reduce seal efficiency. Although one side of the trailer may properly engage the seal, the other will not. As a result, the trailers are not properly sealed, and wind and rain will enter the loading bay.
A still further problem with conventional loading bay trailer seals is that the trailers are often tilted. One side of the trailer is higher or lower than the other. As a result, the sides and top of the trailer do not uniformly engage the seal. Non-uniform engagement generates forces or snags that damage the seal or results in a poor seal. The resulting tears and excessive wear reduce the useful life of the seal.
A still further problem with conventional loading bay trailer seals is that they rely on mechanized controls to adjust for the height and width of the trailer, as well as any angle, tilt or miss-spotting of the trailer. These mechanized controls are expensive and can require frequent maintenance, particularly when improperly used by untrained dock personnel. Mechanized controls also add to labor costs, can damage trailers and dock equipment, and can cause injury to dock personnel.
The present invention is intended to solve these and other problems.